Acoustics
Building codes and standards
Sound insulation/ blocking
Noise pollution
Sound absorption
Soundproofing

Defining the acoustic requirements and regulations for noise control in buildings

Rick Roos
Rick Roos
August 27, 2019

A 5-part guideline for understanding the acoustic standards and comfort criteria in architectural design

Building codes and voluntary industry guidelines are increasingly focusing on the importance of good sound insulation

Getting started with building acoustic standards

Our awareness of the impact that noise has on our daily lives is increasing, as is the role that the building envelope and interior design of a space play in creating good acoustic environments. It makes sense then that legislative requirements and government standards for acoustic design and performance follow suit. Likewise, as updated codes are adopted, so too are the methods for meeting targets set for sound control.

This article discusses the International Building Code requirements for acoustics, voluntary acoustical guidelines, standards in government facilities, provides advice to help you move beyond code compliance in North America toward designing comfortable and productive indoor environments, and much more.

The first article in this series presented a thorough argument about why acoustics need to be considered early in the building design process. To recap, everyone involved in the construction of a new building – from architects and designers, engineers, building owners to contractors, and planners to engineers – share the common goal of ensuring occupant comfort and well-being. Getting acoustics right means consideration of sound isolation requirements, standards specific to your design application, and the goals of the project. 

Acoustic design and engineering can be complex, especially when you consider the various bodies involved in legislating the requirements for acoustic performance and selecting appropriately performing systems. Layer that with the myriad voluntary guidelines for meeting the specifications for high-performance structures and you can see the challenge.

At ROCKWOOL, we take an approach that results in more than just good acoustics but occupant comfort, by providing solutions that comply with standards and deliver the best sound experience based on science and proven acoustical engineering practices. 

PART 1: International Building Code requirements

Building and construction codes address issues important in the design, construction, and operations of buildings. It is important to note that these codes are minimum requirements. Often, building professionals voluntarily choose to set higher performance targets, sometimes in order to meet the criteria for certification programs such as the WELL Building Standard™ and LEED v4 (Leadership in Energy and Environmental Design), to create more liveable and sustainable buildings.

Legally required national codes are, in many cases, different between Canada and the United States at the level of model codes, with each country having its own specifications for how those requirements are implemented. Additionally, each state, province, or territory mandates how building code soundproofing requirements are applied in their jurisdiction. Below we outline how acoustic code requirements are structured across the two countries.

United States

In the United States, the International Building Code (IBC) – current version adopted in 2018 – includes an acoustic/noise requirement, labeled as the STC/IIC stipulation for Group-R occupancies. 

IBC STC requirements

IBC STC requirements apply to occupants of residential buildings (i.e. houses, apartments, condominiums) or places offering overnight accommodations such as hotels and motels. The IBC does not have acoustic requirements for non-residential buildings. The IBC is a model code, which means it is up to each jurisdiction to set and enforce its own codes specific to the needs of its region using the IBC as the guide.

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OSHA sound exposure limits

The U.S. Department of Labor’s Occupational Safety & Health Administration (OSHA) has established standards and limits for occupational noise exposure and hearing protection that go much further to maintain safe sound levels in the workplace. These standards are enforced on a state level to prevent occupational hearing loss by protecting workers, primarily in factories and heavy industries, from excessive noise.

OSHA regulations noise level

The OSHA regulations address noise levels with both construction requirements as well as administrative controls (e.g. changes in the workplace or schedule that reduce or eliminate worker exposure to noise) to maintain OSHA decibel limits outlined in the standards. 

Recognizing that current acoustics codes are often insufficient to meet occupants’ needs, the International Code Council (ICC) has developed a separate set of recommendations, outlined in the ICC G2 – 2010 Guideline for Acoustics. This guideline sets targets for sound isolation performance for construction systems that separate occupied spaces in commercial and multiple-family buildings (e.g. offices, hospitals, schools, condominiums, apartments, dormitories, hotels, and mixed-use buildings). The recommendations in this guideline call for improved acoustical analysis of wall and ceiling assemblies, components or building materials and installation methods, and a more detailed inspection process.

In addition to OSHA, the U.S. has two other federal acts that pertain to acoustics. The Healthcare Information Portability and Accountability Act (HIPAA) requires that design and construction professionals ensure patient confidentiality and take reasonable care to maintain speech privacy requirements with all new construction and renovations of healthcare organizations - i.e. hospitals, pharmacies, and physician’s offices. Also, the Americans with Disabilities Act (ADA) provides requirements for emergency alarm loudness and assisted listening devices for hearing impaired people.

Building code insulation requirements

From thermal resistance requirements to fire safety and acoustical requirements, the myriad building codes and standards related to insulation and the broader built environment will continue to evolve.

For a more thorough overview of the ICC, National Fire Protection Association (NFPA), the ASTM standards, and additional fire regulations, visit our page on North American building codes and standards.

Read this post

Canada

The National Building Code of Canada 2015 (NBC 2015) is similar to the IBC in the U.S. in that it is a national model code. Canada's constitution gives the ten provinces and three territories jurisdiction over the establishment and enforcement of construction codes. Some cities also have autonomy over their own building codes as directed by their provincial authority. 

National Building Code of Canada STC ratings

NBC 2015 includes an extensive section on acoustics. In drafting this most recent version, the National Research Council Canada (NRC) worked closely with industry partners to test and evaluate various building elements and their connections to adjacent building elements. The code takes into account an improved understanding of noise control in buildings (specifically flanking sound transmission). The new requirements are given in terms of apparent sound transmission class (ASTC) rating rather than just sound transmission class (STC).

Other legislation with noise exposure limits in Canada includes the Canada Labour Code, and the Canada Occupational Safety and Health Regulations, both of which have sections on safe decibel levels to protect employees from hearing loss in their work environment. Each of the provinces and territories also has its own legislated requirements around excessive noise.

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PART 2: Voluntary acoustic standards and guidelines

Increasingly, it is understood that when planning acoustic performance, meeting the building codes should not be the goal but rather the starting point.

Today, many building occupants are driving higher expectations and demands from the bottom up. And building owners are more frequently opting to follow voluntary acoustic guidelines or standards for schools, healthcare facilities and offices to make their buildings more appealing to potential occupants as spaces to live, work, learn, and heal.

As a result, building design and construction professionals, including architects and engineers, now regularly look to voluntary guidelines for direction on meeting improved targets for high performance. Depending on the built environment, “high performance” can mean many things such as the building’s function (i.e. is it a healthcare facility or commercial space).

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United States

The Acoustical Society of America (ASA) has its own set of recommended standards. It draws on the American National Standards Institute (ANSI) accreditation for acoustic design. 

There is also ASTM International (an international standards organization formerly known as the American Society for Testing and Materials) which has developed and published international voluntary standards for the acoustic performance of materials and products. ASTM Volume 04.06 (Thermal Insulation; Building and Environmental Acoustics, 2019 edition) includes standards on environmental acoustics, addressing community noise, acoustical materials and systems, mechanical and electrical system noise, open plan spaces, sound absorption, and sound transmission.

ASHRAE (the American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards also address the acoustical requirements of a building. Its handbook includes a chapter on noise and vibration control since HVAC equipment is one of the primary sources of interior noise in buildings. The chapter mentions “mechanical equipment must be selected, and equipment spaces designed, with an emphasis on both the intended uses of the equipment and the goal of providing acceptable sound levels in occupied spaces of the building and in the surrounding community.” These standards are extensive; they follow the source-path-receiver model and identify the different requirements for various building types (e.g. hospitals, schools, etc.).

ASHRAE 189.1 is a specification that can be applied to high-performance “green” buildings other than low-rise residential buildings. It is now used as the technical basis for the International Green Construction Code (IgCC) and may be voluntarily applied by a developer or required by a local government for certain projects. Section 8.3.3 governs the acoustical control for the building envelope, the interior spaces within the building or structure, and the design of the related mechanical equipment and systems.

Canada

Building design and construction professionals in Canada have guidance in navigating the recommended best practices in acoustics planning from the Canadian Acoustical Association (CAA).

The CAA Guide to the Use of Acoustical Standards in Canada summarizes the recommended acoustical and noise control standards from several different organizations. These include ASA/ANSI Standards and ASTM International, as well as CSA Group (a Canadian-based international standards organization), and the Standards Council of Canada (IEC and ISO standards).

Acoustics standards applicable across North America

Codes and standards for acoustics in healthcare

The need for good acoustics in healthcare environments is well understood today. In the United States, the Facility Guidelines Institute (FGI) maintains and improves the written guidelines with acoustics principles addressed in the FGI’s “Sound & Vibration: Design Guidelines for Health Care Facilities” (formerly AIA Guidelines for Healthcare Facility Design). The acoustical criteria outlined in the FGI Guidelines are brought on by both patient privacy laws and evidence of the detrimental effects of hospital noise on patients and staff.

These guidelines contain six sections outlined in the second visual below: site exterior noise, acoustic surfaces, room noise levels, interior wall and floor/ceiling construction, speech privacy, and building vibration. First published in 1947, they are now updated every four years, most recently in 2018.

The 2010 version was the first to include a subsection titled Sound & Vibration: Design Guidelines for Health Care Facilities. They don’t just serve as a guide for regulatory codes, they also outline best practices for those involved in the design of healthcare facilities.

LEED for Healthcare is a building rating system that recognizes the unique needs of those residing and working in healthcare facilities. These healthcare provisions were implemented to “minimize the effect on building occupants of site exterior noise produced by road traffic, aircraft flyovers, outdoor facility mechanical, equipment, and plumbing, and building services equipment,” among other sources of noise pollution.

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Standards for acoustics in schools

Children are among our most vulnerable populations because their auditory development and cognition have not fully developed; as such, the need for a good acoustic environment in schools is increasingly well understood.

Noise can contribute to distraction, lower academic performance, and stress (new research is also suggesting that the noise generated from bathroom hand dryers, often found in schools, is harmful to children). Accordingly, guidelines have been developed to address the specific acoustical needs of educational settings. 

ANSI standards for classroom acoustics

The main standard that addresses this is ANSI/ASA S12.60 with information about acoustical performance criteria, design requirements, and guidelines for schools. There are two parts of interest, Part 1: Permanent schools, and Part 2: Relocatable Classroom Factors (applicable for portables).

S12.60 includes a provision stating that “for high-noise sites (peak-hour Leq above 60 dBA during school hours), implement acoustic treatment and other measures to minimize noise intrusion from exterior sources and control sound transmissions between classrooms and other core learning spaces; projects at least one-half mile (800 meters) from any significant noise source (i.e. highways, trains, and aircraft overflights) are exempt.”

Collaboration for High-Performance Schools (CHPS) and LEED for Schools (see below re: LEED v4) have sections on acoustics based on and in reference to ANSI/ASA S12.60. The overall goal of these voluntary programs is to support healthy learning environments for students and teachers. As it relates to acoustics, these guidelines aim to reduce distraction from noise, reduce strain on teachers and improve collaborative communication in the classroom. 

Supporting and advancing health and wellness of building occupants

The WELL Building Standard™ was developed by The International WELL Building Institute™ (IWBI™) as a standard for building construction with a focus on supporting and advancing human health and wellness. It recognizes the potential impact that built environments can have on occupants. One of the seven concepts that make up the WELL Building Standard is “comfort”. In WELL v2 there is a new ‘sound concept’ which aims to improve occupant health and wellbeing in the built environment through acoustical comfort.

The primary objective here is to reduce the most common sources of distraction and irritation for occupants, as well as to enhance those elements that create a positive experience. Acoustics pre-requisites and optimizations are included in this section “to shape spaces, to mitigate unwanted indoor noise levels, and to reduce exterior noise intrusion in order to enhance social interaction, learning, satisfaction, and productivity.” Specific features of the guidelines take into account reverberation time, sound masking and incorporating sound-reducing surfaces.

Standards for “green” construction have the potential to negatively impact acoustics

LEED v4

Any discussion around sustainable construction practices almost always includes LEED v4. It is the most widely recognized and adopted building rating system globally. In Canada, LEED v4 is administered by the Canada Green Building Council (CGBC); in the United States, by the US Green Building Council. Both parts of LEED that are applicable to schools and healthcare facilities which were discussed above have been incorporated in LEED v4.

Though many environmentally conscious professionals in the industry have moved to adopt the rigorous standards of LEED v4, the implementation of many of its initiatives can at times, unintentionally, degrade acoustical performance. Common complaints around acoustics in “green” buildings include uncontrolled noise and lack of privacy. These issues can occur with the presence of hard, reflective surfaces (e.g. glass, concrete, exposed metal) that don’t absorb sound. In addition, the sound isolation capabilities of walls, roofs, windows, and partitions should be carefully considered during the acoustic design and engineering phases of any project.

Further to the above, the LEED v4 standard for the design of high-performance green buildings lists the following outdoor-indoor transmission class (OITC) and sound transmission class (STC) requirements:

  • OITC and STC requirements where buildings are within five miles of an airport serving 10,000 jets per year,
  • The yearly day-night average sound level (DNL) at the property line exceeds 65dB, or
  • Buildings are within 1,000 ft from a highway/expressway.
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PART 3: Standards for acoustics in government facilities

In the United States, the General Services Administration (GSA) manages all public/federal government facilities. The PBS-P100 Facilities Standards for the Public Buildings Service is GSA's mandatory facilities standard for office buildings.

p100 code

The General Services Administration p100 code applies to the design and construction of new federal office facilities, major repairs and alterations of existing buildings, and lease construction facilities that GSA intends to own or has the option to own. A major requirement of P100 is that federal office buildings must comply with the local building codes and other local requirements unless there is a direct contradiction with another requirement of P100. 

In the case of Federal Court facilities, there is a specific requirement that a qualified acoustical consultant examines situations where outdoor noise could interfere with court activities and set construction requirements to prevent such noise pollution.

P100 requires that all new construction and substantial renovations must achieve a LEED v4 Gold rating, meeting requirements appropriate for the use. The standards provide four levels of performance within which buildings can be categorized. The following are the requirements for the exterior wall assembly, designed primarily for general office use, with the potential to be adjusted for other uses or applications.

  • Baseline: STC-40/OITC-35 based on standard performance values reported for assemblies
  • Tier 1 High Performance: STC45/OITC-40 & site assessment, and lab acoustical testing of enclosure components
  • Tier 2 High Performance: STC45/OITC-40 & site assessment, and site mock-up acoustical testing
  • Tier 3 High Performance: STC50/OITC-45 & site assessment, mock-up field tests, and one field test per 2000 m2 (20,000 ft2) of the enclosure

The U.S. Department of Housing and Urban Development (HUD) requires that when housing is financed or funded by the agency, and outdoor sound levels are in the range between 65 and 75 dBA day-night level, the building must be capable of reducing the interior sound levels to a day-night level of 45 dBA.

Airports and urban interfaces are other areas where the acoustics are being scrutinized. For military mixed-use space or AICUZ (air installation compatibility use zones), the U.S. Department of Defense outlines the recommended noise level reductions based on the surrounding day-night average sound level (DNL). These government standards are not strictly on-base requirements, but as seen in the map below, AICUZ zones have noise thresholds that are measured and adhered to as these aircraft take off and land.

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PART 4: Summary of legislative requirements, standards, and voluntary guidelines in building acoustics*

Category (1 = mandatory code, 2 = voluntary guidelines, 3 = government standards) Acoustics standards or legislative requirements Application(s) (i.e. office, education, healthcare, etc.) Acoustic criteria impacted Jurisdiction (U.S., Canada, Both) Key takeaway
 1 International Building Code  Residential Sound transmission class  U.S. The section on acoustics/noise requirements is labeled the STC/IIC stipulation for Group-R occupancies.
 1 National Building Code of Canada 2015 (NBC 2015)  All Apparent sound transmission class (ASTC)  Canada Includes an extensive section on acoustics with new requirements given in terms of apparent sound transmission class (ASTC) to account for flanking sound transmission.
ASTM     
 2 ASTM C634 – 13e1* Terminology Relating to Building and Environmental Acoustics *Replaces all previous versions of ASTM C634 Offices Environmental acoustics Both Covers terms and definitions related to environmental acoustics. The purpose of this terminology is to promote uniformity of key definitions.
 2 ASTM E413-16 Classification for Rating Sound Insulation *Replaces all previous versions of ASTM E413 Offices Sound transmission class (STC)   Both Covers methods of calculating single-number acoustical ratings for field measurements of sound attenuation obtained in one-third octave bands.
 2 ASTM E1110 - 06(2019)* Classification for Determination of Articulation Class *Replaces all previous versions of ASTM E1110 Offices Speech privacy Both Provides a rating for comparing building systems for speech privacy purposes, designed to correlate with transmitted speech intelligence between office spaces.
 2 ASTM E1179 – 13(2019)* Specification for Sound Sources Used for Testing Open Office Components and Systems *Replaces all previous versions of ASTM E1179 Offices Speech privacy Both States the requirements for sound sources used for measuring the speech privacy between open offices.
 2 ASTM E1332-16* Standard Classification for Rating Outdoor-Indoor Sound Attenuation *Replaces all previous versions of ASTM E1332 Offices OITC Both Provides a method to calculate ratings that can be used for assessing the sound isolation provided by a building.
 2 ASTM E1374 - 18e1*: Standard Guide for Open Office Acoustics and Applicable ASTM Standards *Replaces all previous versions of ASTM E1374 Offices Speech privacy - open and closed offices Both Discusses the principles and interactions that affect the acoustical performance of open and closed offices.
 2 ASTM E1425 – 14* Practice for Determining the Acoustical Performance of Windows, Doors, Skylight, and Glazed Wall Systems *Replaces all previous versions of ASTM E1425 Offices Sound transmission as a function of air leakage Both Establishes requirements for testing and rating acoustical performance of the window, door, skylight, and glazed wall systems.
 ASHRAE     
 2 ASHRAE HVAC All Speech intelligibility U.S. Chapter 48 discusses how the components of the mechanical system may produce sound by the nature of the airflow through and around them. ASHRAE also provides Design Guidelines for HVAC-Related Background Sound in Rooms.
 2 ASHRAE 189.1 All (high-performance green buildings) Reverberation time U.S. Provides complete building sustainability guidance for designing, constructing, and operating high-performance green buildings. It has replaced the International Green Construction Code (IgCC).
 2 2018 International Green Construction Code (section 807) Powered by Standard 189.1-2017 All (high-performance green buildings) Outside Inside Transmission Class (OITC) and Sound Transmission Class (STC) U.S. Replaced by ASHRAE 189.1, the IgCC was a formula for green building codes working toward a new era that includes environmental health and safety as code minimums.
 Others     
 2 FGI (Facility Guidelines Institute) Sound & Vibration: Design Guidelines for Health Care Facilities *AIA Guidelines for Healthcare Facility Design were evolved into FGI’s healthcare guidelines Healthcare facilities Site Exterior Noise, Speech Privacy / Sound Isolation, Speech Intelligibility / Room Finishes, HVAC & Building Systems, Building Vibration Both The acoustical criteria outlined in the FGI Guidelines are brought on by both patient privacy laws and evidence of the detrimental effects of hospital noise on patients and staff.
 2 LEED v4 Offices; specific versions for having been created schools, and healthcare facilities Background noise level (interior), STC, absorption, reverberation time, Noise Reduction Class  Both LEED v4 is the framework and benchmark for the next generation of green buildings.
 2 WELL v1 and v2 Offices, and other building types Sound Pressure Level, reverberation time, sound masking, absorption, STC Both WELL is the leading tool for advancing health and wellbeing in building construction globally based on the impact the built environment can have on occupants.
 2 ISO 3382-3:2012 Acoustics -- Measurement of room acoustic parameters -- Part 3: Open plan offices Offices Room acoustic parameters Both Results of this measurement can be used to evaluate room acoustic properties in open plan offices.
 2  ANSI S3.5-1997 (2017) Methods for Calculation of the Speech Intelligibility Index Offices Speech intelligibility Both Defines a method for computing a measure highly correlated with speech intelligibility.
 2 ANSI/ASA S12.60 Education facilities (i.e. schools) Environmental noise, speech intelligibility Both Two parts of ANSI S12.60 are relevant to acoustics design and performance criteria in schools, Part 1: Permanent schools, and Part 2: Relocatable Classroom Factors (applicable for portables).
 3 PBS-P100 Facilities Standards for the Public Buildings Service Public buildings STC/ OITC U.S. Establishes design standards and criteria for new buildings, repairs, and renovations for the Public Buildings Service.

*Not included in the table above are test methods and laboratory measures as the focus is on standards that impact the day-to-day design and construction phases of a new or renovation project.

PART 5:  Advice: helping you moving beyond definitions and code compliance and toward designing the built environment for acoustic comfort.

Building acoustics is too often given low priority because it competes with several other project goals including sustainable design and development, functionality and aesthetics, and building automation and controls, and is seen as a separate initiative. Taking an integrated design approach is a good place to start.

Although there may be differences in the acoustical requirements of offices, classrooms, healthcare facilities, and other applications or building types, common noise problems affecting the resulting acoustic comfort include the following:

  • Too much noise outside the building entering the space,
  • Too much noise from adjacent spaces, and
  • Lack of sound control in the space itself.

The right stone wool acoustic solutions from ROCKWOOL and Rockfon can reduce unwanted noise and help create a healthier, more productive and less disruptive indoor environment. It’s important to think about legislative requirements, standards, and voluntary guidelines as being designed to ensure a comfortable built environment. Building code insulation requirements for use in fire separations or exterior walls and roofs are an important component of developing acoustic environments that support occupant health, learning, productivity, recovery, safety, and wellbeing.

Designing to high acoustic comfort, along with using low-emitting materials that are resistant to mold and mildew, contributes to improved indoor environmental quality (IEQ). Occupant auditory comfort is essential to their indoor experience and that means controlling noise from exterior sources, as well as acoustic considerations on the interior where the right selection of ventilation, heating, cooling, and privacy may be overlooked.

ROCKWOOL Technical Services Support

Stone wool is a great acoustic insulator and is used in building assemblies to provide STC ratings that deliver occupant comfort in your indoor environment. ROCKWOOL has a number of STC-rated wall assemblies that can meet the architectural specifications. 

Our technical support team is ready to work with you in evaluating whether a particular assembly would satisfy the noise level reduction you are trying to achieve. We’ll also provide you with a recommendation on the right acoustic solutions for your specified requirements. Consider us a partner in your next project.

Contact us

Summary

When planning a building’s acoustic environment, navigating the multitude of codes and standards around managing noise can be complicated. Knowing what is required by law is just the beginning, as more and more building professionals recognize the potential for a better acoustic experience.

The good news is that acoustics is increasingly recognized as a key component of high-performance buildings and the design and construction communities are leading the push to adopt higher standards.

Getting the acoustics right, between the code-driven acoustical sound isolation requirements, numerous voluntary guidelines, standards specific to your design application, and the goals of the project, will ultimately benefit all project stakeholders.

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